Honda-SOHC

SOHC.co.uk Forums => CB750 => Topic started by: Pauarc on May 27, 2024, 01:34:50 PM

Title: Primary chain k2
Post by: Pauarc on May 27, 2024, 01:34:50 PM
Honda cb750k2 Can you check the primary chain on the bike (still in the frame)
Title: Re: Primary chain k2
Post by: K2-K6 on May 27, 2024, 06:41:50 PM
Yes.

Sump pan off and you'll see the "tensioning" wheel from underneath just in front of oil pump.
Title: Re: Primary chain k2
Post by: Pauarc on May 27, 2024, 07:51:39 PM
That’s what I was hoping
Title: Re: Primary chain k2
Post by: Pauarc on May 27, 2024, 08:11:14 PM
How many miles should a chain and tensioner do approximately
Title: Re: Primary chain k2
Post by: Bryanj on May 27, 2024, 08:14:55 PM
How long is a piece of string, it depends on level of thrashing and servicing
Title: Re: Primary chain k2
Post by: Jan B on May 27, 2024, 08:50:53 PM
There is a service limit on the primary chain according to the service manual. Just measure the slack and then you can decide on splitting the cases or not.
Title: Re: Primary chain k2
Post by: archmill on May 27, 2024, 09:42:56 PM
Pauarc, just re-newed the primary chains and tensioner on a 79 F2. The limit on the F2 is 70mm and mine measured 70mm so new chains and tensioner from CMSNL. after fitting, the measurement was 63mm. I think the limit of 70mm is for all 750 SOHC engines but double check.
Title: Re: Primary chain k2
Post by: K2-K6 on May 28, 2024, 09:21:01 AM
They are a pretty durable chain and generally don't display premature wear when used with decent service schedule.

There's schematic in the official manual showing where to measure and asses to chain. Described with vernier caliper in depth measurement from face of oil pan mating surface up to a point on the tensioner arm.

Title: Re: Primary chain k2
Post by: Pauarc on May 28, 2024, 11:39:24 AM
Thanks for the help will have to drop the pan and see
Title: Re: Primary chain k2
Post by: Martin6 on May 30, 2024, 11:49:30 PM
Yes, 70mm for the CB750K. I left mine alone at 68.2mm until I next take the engine out, as I had no other reason to go into the engine case. Maybe should have done it, if I had the opportunity again, I would, but I didn't know the top end would go back together so easily at the time and didn't want to get in above my head.

I have 40,000 miles on mine, so 1.3mm wear or 'stretch' per 10k, if it's linear!
Title: Re: Primary chain k2
Post by: Pauarc on June 03, 2024, 10:34:04 AM
Just checked tensioner and the reading is 67.8 so I think it’s good to go the tension wheel is good no marks